Controllable pitch propeller



Oct. 17, 196i A. M. NAULTY 3,004,609

CONTROLLABLE PITCH PROPELLER Filed July 2l. 1959 6 Sheets-Sheet 1 @10g we Oct. 17, 1961 A. M. NAULTY 3,004,609

CONTROLLABLE PITCH PROPELLER Filed July 21, 1959 6 Sheets-Sheet 2 mamy oct. 17, 1961 A. M. NAULTY 3,004,609

CONTROLLABLE PITCH PROPELLER Filed July 21. 1959 6 Sheets-Sheet 3 Oct. 17, 1961 A. M. NAULTY 3,004,609

CONTROLLABLE FITCH PROPELLER Filed July 21. 1959 6 Sheets-Sheet 4 Oct. 17, 1961 A A. M. NAULTY Filed July 2l, 1959 Oct. 17, 1961 A. M. NAULTY 3,004,609

CONTROLLABLE PITcH PROPELLER Filed July 21. 1959 6 sheets-sheet 6 3,004,609 CONTROLLABLE PITCH PROPELLER Albert M. Naulty, Springfield, Pa., assigner to Baldwin- Lima-Hamlton Corporation, a corporation of Penn= Sylvania Filed July 21, 1959, Ser. No. 828,651 7 Claims. (Cl. Utl-160.32)

This invention relates to adjustable pitch propellers of the type `employing a hydrulically operated servomotor mechanism =for adjusting the blades, and more particularly to an improved mechanism for controlling and operating the servo-motor.

My invention is particularly useful for adjustable pitch marine propellers that require adjusting forces of considerable magnitude. In order to have operating mechanism sufficiently compact so as to be contained in the propeller hub it is desirable to employ hydraulic operating uid under very high pressures. This has created many problems.

One object of my invention is to provide improved means whereby high operating pressures may be effectively suplied to the blade adjusting servo-motor.

A further object is to provide such an improved means that has a high degree of compactness and is relatively economical in manufacture and maintenance considering the necessary complications in a marine-type adjustable blade operating mechanism.

A further object is to provide improved means for insuring complete safety of operation of lthe propeller in the event of power or pressure Ifailure. n

In accomplishing the foregoing as well as other objects I provide in one modification a high pressure pump driven by an electric motor with the pump and motor mounted on the propeller shaft for rotation therewith and preferably mount the motor and pump within the shaft interior and utilize the motor casing as a piston for adjusting the control valve of the blade-adjusting servomotor. In this way I can utilize low pressure overshaft seals for supplying fiuid to the pump whose high-pressure connections are contained entirely within the propeller shaft thereby eliminating the need for high-pressure overshaft seals.

Other objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawings in which:

FIG. 1 is a longitudinal sectional view of my improved control mechanism;

FIG. 1(A) is a Itransverse sectional view taken on the line of .1A- 1A of FIG. 1;

IFIG. 2 is a sectional View of a propeller hub and blades together with the servo-motor control valves, this ligure being connected to the left end of FIG. 1 through usual flanged shaft couplings not shown;

FIG. 3 is a sectional view similar to lFIG. 1 in which an electrical mechanical control is used instead of an all hydraulic control;

FIG. 4 is an enlarged longitudinal section of an automatic pitch locking device taken generally on line 4--4 Y of FIG. s;

FIG. 5 is a transverse section -viewed from the left end of FIG. 4, with part of the mechanism broken away to show a detail of the locking shoe; and

FIG. 6 is a transverse section taken on the line 6-6 of FIG. 2.

As shown in FIGS. l and 2, my invention is disclosed in connection with an adjustable blade propeller having a hub 1 and blades 2 journalled therein which are operated by a hydraulic piston and cylinder servo-mechanism of the type constituting the inventions of R. B. Willi, Patents 2,913,057 and 2,925,131. The iiuid for operatblhbii Patented Oct. 17, 1961 ing the servo-motor is controlled by a valve generally indicated at 3, the details of which do not constitutea part of the present invention. The valve has an axially movable stem 4 extending through the propeller shaft 5 to `a source of operating fluid pressure. Heretofore it has been customary to supply operating fluid through an external manifold, but this entails difficulties that my present invention overcomes.

The operating pressure is supplied by a pump generally indicated at 6 disposed within the shaft and connected to the valve stem 4 to move axially therewith. In addition to serving as a pump, the pump casing 7 functions as an axially slidable crosshead ffor an automatic pitch locking device tol-be described later and for providing operating means for indication of pitch. The pump is specifically shown yfor purposes of illustration as a gear type driven through a shaft 8 by an alectric motor generally indicated at 9 -Whose casing is rigidly connected to the pump casing by an adapter plate 10. Hence the electric motor and pump move together as a unit with movement of the valve stem.

The motor casing also has a pistou portion 11 within a cylinder 12 to provide power means for positioning the valve stem. The piston has differential areas 13 and 14 where the aft area 13 is one-half of the forward area 14. This is used in conjunction with a hydraulic control circuit Iwhereby oil at constant pressure is maintained in the aft chamber of the cylinder and oil is either added to or taken away Ifrom the forward chamber to effect motion. With the differential in area being two-to-one and constant pressure being maintained on the aft chamber the resulting forces in either direction of motion are equal. The aft chamber is closed by a suitable packing gland 15 and the forward chamber is closed by a reduced cylindrical portion 16 of the motor casing extending into a cylinder 17 formed in the housing containing cylinder l2. Usual piston rings 1S are formed in piston 11 and extension 16.

To control the axial positioning of the motor 9 and consequently of the propeller control valve 3 the operator, or helmsman, controls supply and exhaust of pressure fluid to the opposite piston sides 13 and 14, through passages 20 and 21 by a suitable external control valve, not shown herein `as it does not constitute a part of my present invention. The passages 20 and 21, as Well as others -to be described, extend through an overshaft seal 22 of the type disclosed in Willi Patent No. 2,859,054.

The electric motor 9 is continuously driving the pump 7 to generate high pressure that is transmitted `from a pump passage 40 and a valve stem passage 41 to the servo-motor control valve 3 which, in accordance with whatever position it has been moved to by piston 11 will allo-w the high pressure fluid to be transmitted to one end or the other of the servo-motor cylinder 42 to move piston 43 thereby to adjust the angularity of the blades 2 in the manner described in said Willi Patent 2,913,057.

Automatic pitch locking device-In case of failure of pump `6, or of electrical motor 9, or the ships electrical system, or -any other failure that might render the loss of operating pressure to the servo-motor mechanism, I provide means for automatically locking the Valve stem 4 from further motion. The valve stem 4 is bolted directly to the pump crosshead 7 by means of supplemental bolts 5i. Threaded into the crosshead are Ifour crosshead rods S2, FIG. 4. Each -of the four crosshead rods extend axially through coupling flanges generally indicated at 56 to an external location as shown on the longitudinal sectionof FIGURE 4. A stuffing box 53 and rings 54 prevent loss of oil from a shaft cavity 54. Bolted to the external exposed ends of the crosshead rods is a slidable ring 55. Thus, any motion of the valve stem 4 is transmitted to the slidable ring via the crosshead 50 and the crosshead rods 52. Conversely, any motion to the sliding ring can be transmitted to the Valve stem by way of the same crosshead rods and crosshead; therefore, locking the sliding ring 55 from any axial motion will also lock the valve stem from any axial motion and thereby lock the propeller blade in a fixed position within the limits of the control valve 3 clearance.

rThe coupling 56 is keyed in fixed relation to the propeller shaft and has a circumferential extension 56 in the after direction forming anannular space S6" between its inner diameter and the outer dia-meter of the propeller shaft. The inner diameter of this circumferential extension is machined into a series of acme type threads having zero pitch (i.e., -annular rings), generally indicated at 57 on the longitudinal sectional view of FIG. 4.

The slidable ring 55 moves axially in the annular space provided between the shaft diameter and the circumferential extension of the coupling flange. In the slidable ring, spaced 90 apart, are four shoe plates 58, connected respectively to pistons 59 which, in turn, are capable of being pushed outward in a radial direction by springs 60. Initial compression in the springs is controlled by the spring back-up collars 61.

Fluid pressure of the system is transmitted from the gear pump 7, FIG. l, to the shoe plate pistons 59 from main oil pressure passage 40 to oil passages 62, 6.3, 64, 65 and A66. Two of the crosshead rods 52 are used to transmit lluid pressure oil, while the remaining two crosshead rods are used to transmit return oil. The return oil exits to the chamber 54 via a passage 70, a circumferential groove 71 and thus to two of the control rods 52' in a similar manner as lluid pressure oil is transmitted to the pistons 59. As long as there is suflcient lluid pressure to overcome the outward Iforce on the shoe plate due to the effects of centrifugal force and the springs 60', the shoe plates will remain retracted and prevent any engagement between the slidable ring 55 and the teeth in the circumferential extension of the coupling flange. With a loss in system pressure the shoe plates will fly out against the inside diameter of the circumferential extension 56 and will permit axial movement of half the width of -a tooth 57 in either direction, and then will engage with the teeth 57.

Restoration of pressure in the main system will cause the shoe plate piston 59 to pull in the shoe plate 58 unlocking the slidable ring 55' from the circumferential extension 56', thus .allowing axial motion of the slidable ring and in turn the valve stem 4. Under non-rotating conditions means are provided to unlock the mechanism should a mechanical change in pitch be desired. In the end of each crosshead rod 52 that passes the iluid pressure to the slidable ring is located a shut-olf needle valve Si). Closing the needle Valve isolates the pressure passage 63 from the Youter chamber S4' of the shoe plate piston. A removable plug 81 is withdrawn to allow a hand pump (not shown) to be connected to passage 66. The application of pressure then by means of the hand pump will cause the shoe plates to withdraw from their engagement -and allow the slidable ring to be moved, if desired, by applying a mechanical jack 4to the outer ends f rods 52. To prevent fluid from the hand pump bleeding olf to the cooler and filter, a pair of check Valves 81 yare inserted in the pump passages. As an alternative to a mechanical jack, a hand pump (not shown) may be used to supply and exhaust pressure lluid through passages yand 21, thereby to move piston 11 to adjust the propeller pitch.

Indication system-A at plate collar 75 bolted to the slidable ring 55 as shown generally at 76 extends outward through slots 83, in the circumferential extension of the flange coupling, into a continuous ring which moves back and forth axially with the motion of the slidable ring. The axial motion of this ring is transmitted to a non-rotating shoe bushing 77 which in turn actuates a'rack 78, FIGS. 4 and 5. The rack drives the pinion 79 which turns the shaft of an electrical syncro device 79a, FIG. 5, -thus by electrical means remotely indicating the position of the valve stem 4. The base 78a upon which the rack and the syncro device is mounted as by a bracket 78b is slidably supported on a stationary member 78e and is guided by bushings 79h which sense the true axial position o-f the propeller shaft at Vthat point. In this manner shaft compression to the reduction gear flange, shaft vibrations and thrust bearing clearances are eliminated as errors in the indication of the propeller pitch.

In the modification shown in FIG. 3 an electric motor 9i) is employed in place of the piston and cylinder 11 and 12 of FIG. l to shift axially the pump 6 and its driving motor 9 for the purpose of adjusting the servornotor valve 3. The casing of motor 90 is rigidly secured to the shaft 91 as by an end plate and screws 92. A nut 93 is rotatably journalled in the shaft by bearings 94 and'is threaded on a threaded shaft 9S rigidly secured to the casing of a pump motor 96 which in turn is connected to the pump and other structure identical to that shown in FIG. l. Such other structure is given the same reference numbers as in FIG. 1. The motor casing 96 is slidably but non-rotatably mounted in a bore 97 of the shaft section 91. The motor 90 has a pinion 98 which drives idler -gears 99 suitably journalled on the casing'of motor 90. These idler 'gears enmesh with an internal gear 100 formed on yan enlarged end of the nut 93. The motor 9i) is reversible and is controlled through suitable external sliprings (not shown) with leads connected to the motor internally of the shaft. Thus it is shown that upon rotation of the armature of motor 90 the nut 93 will be rotated in one direction or the other to shift the pump motor 96 and associated elements including the control valve 3 thereby to adjust the pitch of the propeller blades.

It will, of course, be understood that various changes in details of construction and arrangement of parts may 'be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim: l

l. A propeller having a hub mounted on a shaft for rotation therewith about the shaft axis, blades journalled in the hub, a hydraulically actuated servo-motor mechanism for angularly adjusting the pitch of the blades, means for supplying operating fluid in either of opposite directions to the servo-motor Vto reversely operate it and correspondingly adjust the blade pitch, said supply means including a unidirectional operating pressure fluid pump supported by the shaft for rotation there-with, a valve supported by said shaft for rotation therewith and beingV movable in either of opposite directions to control the direction of lluid supply to the servo-motor, and servo-motor means also supported by and rotatable with the shaft for controlling the operation of the valve to determine the blade adjustment. l

2. The combination'set forth in claim l further characterized by the provision of means for supporting both the valve and the pump internally of the shaft for movement axially thereof, means operatively connecting the valve and pump together, hydraulically operated piston and cylinder servo-motor elements also located Within the shaft, one of said elements being connected to the pump to move it and thevalve axially, and means for supplying pressure iluid to said piston and cylinder elements for controlling the axial position of said pump and Valve and thereby control the blade adjusting servomotor so as to vary the blade pitch.

3. A propeller having a hub mounted on a shaft, blades journalled in the hub, a hydraulically actuated servomotor mechanism for angularly adjusting the pitch of the blades, means for supplying operating iluid to the servo-motor including a pressure fluid pump supported by the shaft for rotation therewith, means for supporting the pump internally of the shaft so as to have movement axially thereof, an electric motor connected to the pump for driving the same and also having axial movement with the pump as a unit therewith, a control valve for the fluid supply to the blade adjusting servo-motor, said control valve being connected to the pump and its electric motor for axial movement therewith, and means for axially moving the pump and its electric motor to operate said control valve.

4. A propeller having a hub mounted on a shaft, blades journalled in the hub, a hydraulically actuated servomotor mechanism for angularly adjusting the pitch of the blades, means for supplying operating fluid to the servomotor including a pressure fluid pump supported by the shaft for rotation therewith, means for supporting the pump internally of the shaft so as to have movement axially thereof, an electric motor connected to the pump for driving the same and also having axial movement with the pump as a unit therewith, a control valve for the fluid supply to the blade adjusting servo-motor, said control valve being connected to the pump and its electric motor for axial movement therewith, piston and cylinder elements one of which is connected to the electric motor for axially moving the pump and its electric motor to operate said control valve, and means for supplying pressure fluid to said piston and cylinder elements from a point externally of the shaft, whereby said external pressure supply may be of low magnitude and the pump pressure of higher magnitude.

5. A propeller havin-g a hub mounted on a shaft, blades journalled in the hub, a hydraulically operated servomotor operated mechanism movable axially of the shaft for angularly adjusting the pitch of the blades, means for locking the blades in position including a stationary member and another member movable axially by the servo-motor operated mechanism, releasable interlocking means between said members, means for releasing the engagement of the interlocking members by pressure uid supplied to the hydraulic blade adjusting servo-motor,

and means for causing said interlocking members to be engaged upon failure of the servo-motor fluid.

6. A propeller having a hub mounted on a shaft, blades journalled in the hub, a hydraulically servo-motor operated mechanism movable axially of the shaft for angularly adjusting the pitch of the blades, means for locking the blades in position including a stationary member and another member movable axially by the servo-motor operated mechanism, rcleasa'ble interlocking means between said members, means for releasing the engagement of the interlocking members by pressure fluid supplied to the servo-motor, means for causing said interlocking members to be engaged upon failure of the servo-motor pressure fluid, and manually controlled means for releasing the automatic pitch locking device to permit emergency manual pitch change even in the event of failure of fluid pressure.

7. A propeller having a hub mounted on a shaft for rotation therewith about the shaft axis, blades journalled in the hub, a hydraulically actuated servo-motor mechanism for angularly adjusting the pitch of the blades, a pressure fluid pump and a valve connected thereto for supplying operating uid in either of opposite directions to the servo-motor to reversely operate it and correspondingly adjust the blade pitch, said pump and valve being disposed internally of the shaft for movement axially thereof, and servo-motor means also located internally of the shaft for moving the pump and valve axially to control the blade pitch.

References Cited in the file of this patent UNITED STATES PATENTS 2,523,053 Obrist Sept. 19, 1950 2,812,026 Braddon Nov. 5, 1957 2,882,975 Hirsch Apr. 2l, 1959 2,913,057 Willi Nov. 17, 1959 

